1. Field of the Invention
The present invention relates to a safety device for a vehicle and, more particularly, to a device for controlling behavior of a seat belt in the event of a vehicle collision or accident.
2. Description of the Related Art
In general, to prevent an excessive impact from being applied to a driver by a constraint force of a seat belt webbing in the event of a vehicle collision, a load limiter for releasing a fixed amount of the webbing when an operation load above a reference value is applied to the webbing is typically installed on a seat belt in a vehicle. The load limiter of the vehicle is a system that is applied to the seat belt along with a pretensioner and thereby doubly protects a driver along with an airbag. The load limiter may be applied to the seat belt in various types of operation structures.
Conventionally, the load limiter is generally mounted in the vehicle so as to meet specific speed regulations. Thereby, when the vehicle has a collision while traveling at the specific speed, the load limiter provides proper operability. However, the load limiter does not provide optimized performance at speeds other than the specific speed, and thus fails to be effective in reducing the chance of an injury to an occupant in those instances.
For instance, the mechanism shown in FIG. 1, is thought to be unreliable because an overshoot phenomenon may occur in which an applied load exceeds a reference load, causing the webbing to be released when the applied load is higher than the reference load. Alternatively, a lock dip phenomenon may occur, causing the webbing to be released at a fixed amount in the initial stage of the operation of the seat belt.
The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.